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Hifararp 


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:y.  /rr//7/y.- 


"  If  one  does  things  well,  though  his  home 
be  in  a  wilderness,  a  beaten  path  will,  by  and 
by.  be  trodden  to  his  door." 


rillinc)  Poof  Ccincils 


THE  AID  or 


DIAGRAMS  AND  CHEMICALS 


GcoRGi:  w.  Weld,  a\.d.,d.d.5., 

NEW    \OQ\\ 


KARJES   & 

532  SIXTH  AVENUE 


-PRICE,  ONE    DOLLAR. 


U'45' 


Entered  according'to  Act  of  Congress  in  the  year  iSgy 

By  George  W.  Weld.  M.D.,D.D.S., 

in  the  office  of  the  Librarian  of  Congress,  at  Washington. 


PREFACE. 


■n^HE  few  diagrams,  that  may  be  of  aid  in  finding  tlie  entrance 
to  difficult  root  canals,  were  originally  embodied  in  a 
lecture  given  to  the  students  of  the  New  York  Dental  School 
in  March,  and,  at  a  later  period,  at  the  Annual  Meeting  of  the 
Seventh  District  Society  of  the  State  of  New  York. 

The  author  has  received  so  man}-  complimentary  letters 
both  from  students  and  practitioners,  stating  in  effect,  "We 
never  knew  how  easily  difficult  root  canals  could  be  disinfected 
and  filled  until  we  adopted  your  ideas,"  that  he  is  prompted  to 
ofTer  them  to  the  profession,  together  with  the  queries  and 
answers  relating  to  the  Chemico-Metai,i,ic  Method. 


SYNOPSIS. 

PAGrr 

Illustrations 7 

Diagrams  for  Inferior  Molars 8 

Diagrams  for  Superior  Molars 10 

Diagrams  for  Bicuspids 11 

Filling  Root-Canals  by  the  Aid  of  Chemicals 13. 

Dr.  Schreier's  Method 13 

Dr.  Barker's  Method 14 

Dr.  Calahan's  Method 14 

The  Author's  Method 14 

Dr.  Perry's  Method 15 

Chemistry  of  the  Chemico-Metallic  Method i6 

Actionof  Nitro-hydrochloric  Acid — Dental 16 

Formation  of  "Albuminates'' 16 

Nature  of  Gases  Generated 16 

Energy  of  Acids  upon  Points 17 

Permanency  of  Asepsis 17 

If  Point  be  pushed  through  Apical  Foramen iS 

If  Gas  should  go  through  Foramen iS 

Filling  Canals  where  there  is  Inflammation  19' 

Filling  by  first  putting  Broach  into  Acid ig 

Necessity  of  Extirpating  the  Dead  Pulp 19 

Filling  Immediately [9 

Filling  with  an  Exposed  Pulp 19 

Length  of  Time  Method  in  Use 20 

Filling  followed  by  Extraction 20 

Blind  Abscess 20 

Root  Disturbance  following  Operation 20 

Disinfecting  the  Dental  Fibrillse 21 

Discoloration  22 

Balsam  of  the  Desert 22 

Phosphate  and  Carbonate  of  Lime 12 

Other  Chemicals , 23 


PRACTICAL  . 


SCIENTIFIC 


—View  of  superior  molar  disin- 
fecled  iiiifl  filled  bv  the  Chem- 
ico-rietallic  net'hod.  Rouls 
filed  away  showing  metal,  al- 
ijuniinate,  etc.  ;   time  ot  oper- 

putrpscent  j>uli>  in  the  buccal 
root  canals  not  extracted. 
Photographed   from  the  orig- 
inal tooth.    Harjes  &  Wright, 
New  York. 


A. — Anterior  view  of  anterior  root 
of  lower  molar  with  two  nei've 
canals  disinfected  and  filled 
by  the  Chemico  -  rietaliic 
Hethod  ;  root  filed  away, 
showing    metal,    albuminate, 


etc.       lime   ot    i 

three    minutes  ; 

pulp  in  canals  not" extracted 

Photographed   from   the  orig 

iiial  tooth.    Harjes  &  Wright, 

New  York. 


■;k- 


'V^ 


ill 


Sup 


cri"-  ,:!!,,  ,.i,id 
with  two  canals  and 
two  foramens;  time 
r»f  operation,   three 

Photographed  from 
original  tooth — H.  & 
W.,  New  York. 


Bayonet-shape  superior 
'  bicuspid,  showing 
adaptation  of  metal- 
lic broach  to  the 
curvature  of  root : 
time    of    operation, 

Photographed  from 
original  tooth— H.& 
W.,  New  York. 


Sup 


^r  bicuspid  with- 

foramen  and  two 

delicate,  hair  -  like 
canals  converging ; 
time  of  operation, 
three  minutes. 
Photographed  from' 
original  tooth— H.  & 
W.,  New  York. 

.  .  .  PERFECT 


DELICATE  .  .   . 

The  method  pre-supposes,  as  a  rule,  no  loss  of  tooth  sub- 
stance ;  that  wherever  one  of  the  finest  Donaldson  Steel 
Broaches  can  be  introduced  into  a  root  canal,  whatever  its 
length,  whether  straight  or  tortuous,  whether  filled  with  semi- 
devitalized  matter,  or  putrescent  pulp  and  fetid  gases,  that 
canal  can  be  disinfected  and  filled  within  a  period  of  five 
minutes  ;  that  the  chlorine  gas  employed  tends  to  disinfect  the 
dentinal  fibres  in  the  roots,  assuring  permanency  of  asepsis. 

(7) 


DIAGRAMS  TO  AID  THE  STUDENT  IN  FINDING 

THE  ROOT=CANALS  IN  SEMI-DEVITALIZED 

TEETH. 

Inferior  Molars. 


The  anterior  root  oi  an  inferior  molar  has,  almost  invaria- 
hly,  two  small  canals  converging  towards  one  foramen  ;  some- 
times, however,  there  are  two  foramens.  The  posterior  root,  as 
a  rule,  has  one  large  canal  ;  sometimes  a  slit  or  ribhon-shaped 
canal;  sometimes  two  canals,  corresponding  with  the  canals  in 
the  anterior  root. 

Let  Fig.  A  represent  the  usual  variety  of  root  canals  of  the 
inferior  molars;  the  crown  having  been  cut  off  near  the  margin 
of  the  gum,  a  cross  section  of  the  tooth  is  brought  to  view. 


Fig.  a. 

a  represents  the  large  posterior  canal  in  the  posterior  root; 
i,  d,  the  two  anterior  canals  in  the  anterior  root.  If  connecting 
lines  be  drawn  between  the  three  dots,  we  find  that  we  have, 
as  shown  in  Fig.  B,  an  equilateral  triangle,  with  the  base  of  the 
triangle  near  the  anterior  portion  of  the  tooth, and  the  entrance 
to  the  canals  at  each  angle. 


Fig.  B. 

Fig,  C  is  the  same  as  Fig.  B  with  the  addition  of  a  hori- 
zontal line,  which  indicates  a  "slit"  or  ribbon-.shaped  canal. 


Fig.  C. 

The  entrance  to  the  posterior  canal  is.  however,  always  to  be 
found  at  the  apex  of  the  triangle.  When  the  posterior  root  has 
two  canals,  the  diagram  is  changed  to  a  square,  as  seen  in  Fig. 
D,  and  the  entrance  to  the  canals  is  to  be  found  at  each  corner 
of  the  square. 


Fig.  D. 

When  the  two  roots  descend  from  near  the  centre  of  the 
tooth  the  square  is  changed  to  a  parallelogram,  as  seen  in  Fig. 
G,  and  the  entrance  to  the  canals  will  be  found  at  each  corner 
of  the  parallelogram. 


Fig.  G. 

In  gaining  entrance  to  the  canals  in  the  anterior  root,  it  is 
necessary  that  the  student  should  bear  in  mind  the  importance 
of  knowing  the//;/ i'(y'(7//ir6)a(//  to  the  canals,  forit  is  oftentimes 
possible  to  introduce  a  fine,  smooth  broach  when  it  is  impossible 
to  introduce  a  broach  with  a  single  hook  or  a  number  of  hooks. 

Fig.  H  is  a  photograph  of  the  anterior  canals  of  an  inferior 
molar,  with  smooth  broaches  inserted,  showing  the  sinuosity 
of  the  canals. 


It  will  be  observed  that  the  line  of  approach  to  the  buccal 
canal  is  from  behind  forward  at  an  angle  of  45  degrees,  and 
from  within  outward  at  an  angle  of  about  60  degrees. 

How  is  it  possible  to  enlarge  such  a  canal,  with  such  an 
environment  with  anj'  kind  of  a  drill  ? 

The  line  of  approach  to  the  lingual  canal  is  from  without 
in  an  inward  direction.  Such  canals  can  be  disinfected  and 
perfectly  filled  by  the  Chemico-IMctallic  Method  in  a  very  short 
space  of  time,  and  at  the  first  sitting. 

Superior    Molars. 

As  a  rule  the  palatine  root  canal  of  superior  molars  is  easy 
of  access,  large  enotigh  to  admit  of  a  barbed  broach,  and  the 
thorough  extirpation  of  the  pulp.  It  is  an  exception  to  the 
rule  if  abscesses  form  upon  this  root.  It  is  the  delicate,  tortu- 
ous, buccal  root- canals,  containing  a  small  quantity  of  dead 
animal  matter  and  mephitic  gases,  and  into  which  it  is  impos- 
sible to  introduce  barbed  broaches,  that  create  root  disturbance, 
and  finally  ulceration. 

Fig.  I  represents  a  cross  section  of  a  right  superior 
molar  at  or  near  the  margin  of  the  gum.      The  dots  represent 


the  entrance  to  the   canals.      If  connecting  lines  be  drawn 
between  the  dots  we  find,  as  observed  in  Fig.  J,  that  we  have 


Fig.  J. 

an  oblique  triangle  with  the  apex  at  the  palatini  portion  of  the /. 
tooth,  and  the  base  near  the  buccal  side  ;  the  hypiatcnuiia  being 
longer  at  the  anterior  cervical  portion  places  the  posterior  apex 
of  the  base  near  the  buccal  and  posterior  central  portions  of  the 
tooth;  the  entrances  to  the  canals  are  found  at  the  points  of  the 
triangle. 

(10) 


Fig.  K  is  a  photograph  of  a  right  upper  molar.  The  line  of 
approach  is  .shown  bj-  smooth  broaches  inserted  into  the  three 
canals.      Thus  we  observe  that  the  line  of  approach  to  the  pala- 


FiG.  K. 

tine  canal  is  from  without  in  an  inward  direction  at  an  angle  of 
about  45  degrees;  the  line  of  approach  to  the  anterior  buccal 
canal  is  from  behind  in  a  forward  and  outward  direction  at  an 
angle  oftentimes  of  more  than  60  degrees;  that  of  the  posterior 
buccal  canal  from  a  perpendicular,  slightly  backward  and  out- 
ward direction;  the  simiosity  of  the  canals,  of  course,  varj-ing 
in  different  roots. 

Of  all  the  root  canals  in  the  molars,  the  anterior  buccal 
canal  of  a  superior  molar  is  probably  one  of  the  most  difficult  to 
disinfect  and  fill.  This  is,  in  part,  due  to  the  line  of  approach, 
which  as  above  stated  is  sometimes  at  an  acute  angle  from  be- 
hind in  a  forward  and  outward  direction,  and,  in  part,  because 
the  canal  is  extremely  delicate  and  tortuous. 

Bicuspids. 


The  bicuspid  teeth  present  a  variety  of  root  canals.  The 
large,  straight  root,  with  one  canal ;  two  small  roots,  with  two 
small  canals  ;  one  root  with  one  foramen,  with  two  tortuous 
hair-like  canals  converging  ;  one  root  with  two  foramens  and 
two  tiny  canals.  As  in  the  case  of  the  other  teeth  where  the 
root  is  straight  and  the-  canal  large  enough  to  introduce  a 
barbed  broach,  ther&  is  but  little  diflBculty  in  the  way  of  extir- 

(II) 


pating  the  pulp  and  disinfecting  and  filling  the  canal,  but  when 
there  are  two  canals,  the  difficulty  increases  in  proportion  to 
their  delicacy  and  sinuosity. 


Fig.  L. 


Fig.  L.,  is  a  photograph  of  a  right  superior  bicuspid  with  two 
delicate  canals  and  two  foramens.  The  entire  tooth  has  been 
filed  away  on  its  anterior  aspect,  showing  the  pulp  chamber, 
pulp  canals,  and  the  palatine  and  buccal  horns  of  the  pulp.  It 
will  be  observed  that  the  buccal  horn  of  the  pulp  extends  much 
nearer  the  point  of  the  buceal  cusp  than  the  palatine  horn 
does  toward  the  point  of  the  palatine  cusp.  This  is  almost  invar- 
iably the  case,  and  it  may  be  said  in  this  connection,  that  on  this 
account  the  danger  of  exposing  and  injuring  a  pulp  in  excava- 
ting" a  cavity  is  generally  from  the  buccal  side.  The  same 
rule  applies  to  the  buccal  side  of  all  the  molar  teeth.  The 
liability  of  such  an  accident  is  lessened  considerably  by  using 
on  the  buccal  surface  of  such  cavities,  round  or  spoon-shaped 
instruments,  rather  than  those  shaped  like  a  hatchet  or  hoe. 

The  diagram,  which  may  assist  in  locating  the  entrance  to 
the  two  pulp  canals  of  a  superior  bicuspid,  is  that  of  a  modified 
dumb-bell,  i.e.,  a  line  with  a  small  ball  on  each  end,  placed  in 
the  cavity  from  without,  in  an  inward  and  downward  direction, 
at  an  angle  of  45  degrees.    See  Fig.  M. 


FILLING  ROOT=CANALS  BY  THE  AID  OF 
CHEMICALS. 


Two  opinions  are  held  by  dentists  of  two  different 
schools  relating  to  the  filling  of  root-canals.  One  that  they 
should  be  filled  permanently  and  solidly,  the  other  that  they 
should  be  filled  with  some  filling  material  that  may  be  easily 
removed  in  case  of  root  disturbance. 

The  first  plan  "is  based  on  the  principle  that  healthy  con- 
ditions of  the  tissues  at  the  end  of  the  fang  established  there  is 
little  danger  of  inflammation  afterward  occurring,  and,  that  if 
it  should  happen,  the  treatment  should  be  external  and  on 
general  principles.  " 

It  has  always  seemed  rational  to  believe,  irrespective  of  the 
different  opinions  governing  the  proper  treatment  and  filling  of 
pulp  canals  that  the  enamel  of  a  tooth  is  to  the  crown  about 
what  the  shingles  are  to  a  house;  and  the  roots  of  teeth,  what 
the  foundation  is  to  a  building. 

In  filling  the  difficult  root-canals,  we  are  also  confronted 
with  the  ideas  of  two  different  schools. 

On  the  one  hand  it  is  claimed  that  they  should  be  enlarged, 
by  the  use  of  reamers  and  barbed  broaches,  and  afterwards 
cleansed,  disinfected  and  filled.  On  the  other  hand  that  as  it 
is  an  impossibility  to  enlarge  the  delicate,  crooked  root-canals 
with  instruments,  or  to  extirpate  thedead  or  semi-dead  matter, 
which  the}"  contain,  the  next  best  and  most  practical  method 
is  to  employ  as  a  substitute  some  chemical  that  will  coagulate 
the  dead  animal  matter  and  correct  the  putrescent  condition  of 
their  contents.  Dr.  Schreier,  of  Vienna,  I  believe  was  the  first 
to  introduce  a  method  for  cleansing  and  disinfecting  root- 
canals  by  chemical  means. 

The  principle  embraced  by  his  method  consists  in  the  de- 
composition of  the  watery  portion  of  the  dead  pulp  fibres  and 
the  production  of  sodium  and  potassium  hydrates  by  intro- 
ducing into  the  root-canal  a  combination  of  potassium  and 
sodium.  Dr.  Schreier  claims  that  this  in  connection  vnth  a 
high  temperature  acts  as  a  germicide ;  and  that  the  shreds  of 

-       '       (13) 


the  pulp  left  in  the  canal  are  transformed  into  a  "soapy  mass," 
which  can  be  removed  by  a  stream  of  water  from  a  syringe. 
The  last  claim  will  doubtless  hold  good  for  the  large  canals, 
but  the  delicate  canals  would  appear  to  be  too  small  to  admit 
of  such  a  procedure.  Dr.  D.  W.  Barker's  method  consists  in 
the  emplo3'ment  of  the  permanganate  of  potash  and  the  perox- 
ide of  hydrogen.  Dr.  Barker  claims  that  the  union  of  these 
two  materials  in  a  pulp-canal  sets  free  the  nascent  oxygen. 
The  operation  is  performed  by  introducing  into  the  canal  upon 
a  Donaldson  bristle  a  little  of  the  powdered  permanganate  of 
potash,  and  then  applying  a  drop  of  the  peroxide  of  hydrogen. 
This,  it  is  claimed,  causes  an  intermediate  change  in  the 
character  of  the  remaining  pulp  tissue  and  the  pus  products. 
Both  of  these  methods  only  provide  for  the  disinfection  of 
putrescent  canals,  the  filling  being  an  after  consideration.  The 
sulphuric  acid  treatment  of  Dr.  Calahan  consists  in  a  destruc- 
tive process  of  enlarging  the  canals  by  the  application  of  a  few 
drops  of  sulphuric  acid  diluted  with  fifty  per  cent,  water.  The 
filling  material  for  the  same,  as  in  the  above  mentioned 
methods,  being  left  to  the  discretion  of  the  operator.  Sulphuric 
acid  is  doubtless  one  of  the  most  deadly'  and  corrosive  of  all  the 
acids.  Its  action  is  difficult  to  control.  Under  certain  con- 
ditions, however,  it  appears  to  be  harmless. 

For  instance,  when  a  small  metallic  point  composed 
principally  of  zinc  is  immersed  in  strong  sulphuric  acid,  the 
point  is  not  attacked,  at  least,  to  any  degree.  An  insoluble 
sulphate  is  formed  upon  the  surface.  The  addition  of  water 
dissolves  the  coating  and  chemical  action  begins.  But  if  one 
of  the  points  be  immersed  in  nitro-hydro-chloric  acid,  it  is 
almost  instantly  dissolved. 

On  the  other  hand  if  a  napkin  be  laid  upon  a  plate  and  sul- 
phuric acid  poured  over  it,  that  part  of  the  linen  which  is  in 
contact  with  the  acid,  will  in  a  short  time  be  completely 
destroyed. 

Place  another  napkin  in  nitro  hydro-chloric  acid  for  the 
same  length  of  time  and  the  linen  is  not  apparently  injured. 

Thus  an  acid  which  quickly  destroys  a  metallic  substance 
has  but  little  effect  upon  linen,  and  vice  versa,  the  acid  which 
destroys  the  napki  n  leaves  the  metal  comparatively  free  from 
injury. 

The  author's  " Chemico-Metallic  Method"  consistsof  the  in- 
troduction of  a  smooth  metallic  point,  composed  principally  of 
zinc  into  the  root-canal,   and   the  application  of  a  drop  of  a 

(14) 


modified  nitro-hydro-chloric  acid.  It  is  claimed,  that  the 
metallic  points  being  extremely  sensitive,  neutralize  the  acid; 
that  after  chemical  action  has  taken  place  the  metallic  point  is 
corroded;  that  an  acid  albuminate  is  formed  and  the  dead  or 
semi-dead  animal  matter  coagulated.  The  point  is  then 
broken  off  in  the  canal  thus  obliterating  space,  and  perma- 
nency of  asepsis  is  assured  by  the  chemical  action  which  takes 
place  in  the  root-canal. 

Whichever  one  of  the  above  mentioned  methods  is  the  most 
practicable,  which  one  presents  the  least  obstacle  for  usefulness 
in  every  indicated  case,  must  be  left  to  time  and  the  experience 
of  the  intelligent  dentist. 

The  application  of  any  chemical  is  intended,  as  a  rule,  only 

for  the  delicate  tortuous  canals,   that  will  not  admit  of  the 

introduction  of  a  barbed  broach  for  the  purpose  of  extirpating 

the  putrescent  pulp,  nor  the  obliteration  of  space  by  the  em- 

'ploj-ment  of  the  usual  filling  materials. 

Dr.  Safford  G.  Perry  of  New  York,  in  an  able  article  pub- 
lished in  the  lutcynational  Dental  Journal,  Sept.  1S95,  entitled, 
"Which  Method  of  Root-Canal  Filling  will  Completely  Obli- 
terate Space,"  saj'S  in  referring  to  the  delicate  root-canals: 

"Let  us  not  deceive  ourselves  by  believing  that  into  such  a 
minute  hole,  closed  atone  end  and  full  of  air,  we  can  pump 
either  of  the  materials  in  such  a  way  as  to  obliterate  space. 

''With  a  minute  opening  at  the  end  of  the  root  for  the 
e.scape  of  the  air,  it  might  be  done,  but  in  the  mouth   it  is  an 

impossibility The  only  way  is  to  leave  the  instrument 

itself.'' 

Dr.  Perry's  method  consists  of  the  introduction  into  the 
delicate  canals  of  a  small  piece  of  gold  or  platinum  wire,  after 
first  smearing  the  same  with  chloro— percha. 

Dr.  Perry's  method  approaches  nearer  the  Chetnico- 
iifetallic  IMcthod.  than  any  other  system  ever  presented  to  the 
profession.  He  doubtless  obliterates  space,  but  there  can  be 
but  little  if  any  chemical  action  associated  with  his  method; 
none  between  the  metal  employed  and  the  chloro-percha,  and 
very  little  if  any  between  the  chloro-percha  and  the  dead 
animal  matter  in  the  root-canal. 


(15) 


The  Chemistry  of 
•WELDS  CHEniCO  HETALLIC  HETHOD," 

By  ALFRED  J.  COHN,  Ph.  D. 
New  York. 

( 1 )  What  is  the  action  of  nitro-hydrochloric  ( dental )  acid, 
containing  a  gum  resinous  matter,  upon  a  metallic  pin  composed 
of  silver,  tin  and  zinc  ;  principally  zinc? 

All  authorities  are  agreed  in  stating  that  when  Nitric  and 
Hydrochloric  Acids  are  mixed,  the  ultimate  product  will  be 
practically  a  solution  of  Chlorine  gas,  Nitrosyl  Monochloride, 
NO  CI,  and  Nitrosyl  Dichloride,  NO  C1-,  in  water;  these  being 
formed,  as  shown  in  the  following  equation  :  3H  N03-f  9H  Cl  = 
5CI+2NO  Cl+NO  Cl---(-6H=0.  Hence  metals  brought  into  con- 
tact with  the  mixture— known  by  the  name  cf  Nitro-Hydro- 
Chloric  Acid — are  converted  into  Chlorides,  partly  from  the  free 
Chlorine  present,  partly  from  the  Chlorine  liberated  from  the 
unstable  Nitrosyl  compounds;  and,  when  an  excess  of  the  acid, 
more  particularly  when  warm,  is  present,  the  higher  Chlorides 
are  formed  :  e.  g  An  becomes  Au  CI3,  Sb  becomes  Sb  Cls,  Fe 
becomes  F'e-'  Cl'\  etc.  It  is,  however,  well-nigh  impossible  to 
sa)'  what  further  complications  would  be  caused  by  the  disturb- 
ing presence  of  the  excess  of  Nitric  Acid  and  gum-resinous  mat- 
ter present  in  the  Nitro-Hydrochloric  (Dental)  Acid;  there  may 
perhaps  be  Nitrates  formed  in  small  quantity  along  with  the 
Chlorides,  or  perhaps  only  Nitrates  of  the  metals  mentioned. 

(2)  Is  an  albuminate  formed  as  claimed  by  Dr.  Weld? 
Albumins  coming  into  contact  with  Acids  are  known  to  be 

converted  into  Acid-Albuuiins,  designated  also  by  the  generic 
name  "Albuminates,'' — this  appellation  being,  however,  an  im- 
proper one,  since  it  would  imply  a  compoundofAlbuminic  Acids 
with  some  base,  which  is  not  the  case.  The  action  of  the  Nitro- 
Hydrochloric  Acid,  etc.,  acting  upon  the  albuminous  matter  in 
the  tooth,  would  no  doubt  result  in  the  formation  of  such  Acid- 
Albumins,  with  coagulation  besides,  and  it  is  not  at  all  unlikely 
that  so-called  "  Albuminates  "  of  the  metals  employed — that  is, 
compounds  of  Albumin  with  the  Silver,  Tin  and  Zinc — would  be 
formed. 

What  is  the  nature  of  the  gases  generated,  and  does  the 

(16) 


chemical  action  upon  the  dead  organic  matter  left  in  a  root-canal 
prove  a  powerful  germicide  ? 

The  gases  most  likely  to  be  formed  in  the  root-canals,  as  the 
result  of  the  action  of  the  acid  employed  on  the  metals,  would 
be  Nitrous  Acid  and  perhaps  Chlorine,  either  or  both  of  which 
would,  no  doubt,  be  thoroughly  germicidal  on  account  of  their 
powerfully  destructive  effects  on  all  organic  matter. 

(4)  Is  the  energj'  of  the  acids  first  directed  to  the  metallic 
broach  inserted  in  the  root  ? 

Acids  usually  seek  to  combine  with  substances  for  which 
they  have  the  most  aflSnity,  and  in  this  case  the  metals  would 
no  doubt  be  attacked  b}^  preference,  although  it  is  highly  reason- 
able to  believe  that  the  contiguous  tooth  substance  would  be 
attacked  to  some  extent  too. 

( 5 )  Is  permanency  of  asepsis  probable  ? 

Where  absolute  absence  of  air  is  obtained,  complete  asepsis 
may  be  assumed  to  be  permanent;  but  whether  such  a  condition 
can  be  obtained  and  be  made  permanent  in  a  tooth  cavit}-  and 
root  canal  can  only  be  ascertained  by  continued  experiment. 

^/         ,  ^^-  .       ,  . 


^ 


7^.C^  "^^'  ^ 


(17) 


QUERIES. 


The  following  queries  have  been  propounded,  from  time  to 
time,  by  different  dentists,  regarding  the  rationale  of  the  pro- 
cess of  disinfection  and  filling  the  difficult  root  canals,  by  the 
Cheinico-JMetallic  Method.  The  answers  are  given  with  the 
sincere  hope  that,  if  there  are  any  errors,  they  may  lead  to 
other  enquiries  which,  in  the  end,  will  prove  of  benefit  to  the 
profession. 

( 1 )  "  What  would  be  the  effect  if  one  of  the  broaches  be 
pushed  through  the  apical  foramen?  " 

A  somewhat  similar  question  was  asked  Stephenson,  viz : 
"  What  would  beco:ne  of  a  cow-  supposing  it  got  on  the  railroad 
track  in  front  of  your  engine?  "  Stephenson,  it  is  said,  replied 
that  it  would  be  bad  for  the  cow. 

In  the  first  place,  there  is,  in  the  difficult  root-canals  oj 
adults,  only  about  one  in  ten  where  the  foramen  is  open.  If  an 
operatorlacksthedelicatesenseof  touch  possessed  by  a  majority 
of  dentists,  ignores  a  manifestation  of  pain  from  his  patient, 
and  carelessly  plunges  his  instrument  through  the  apical  fora- 
men, and  permits  it  to  remain  there — well,  it  would  be  bad  for 
the  tooth.  The  great  trouble  heretofore  has  been  to  properly 
disinfect  and  fill  a  root-canal  near  the  apical  foramen.  The 
possibility  of  going  through  the  foramen  of  the  difficult  root- 
canals  is  very  remote. 

(2)  "Will  not  the  gas  which  is  formed  in  the  canal  go 
through  the  foramen  and  irritate  the  surrounding  tissue  ?  " 

In  the  first  place  in  a  large  majority  of  the  o'/^V;///  root- 
canals,  above  mentioned  the  foramen  is  closed,  at  least  to  a  great 
extent,  which  prevents  the  possibility  of  such  an  occurrence. 
In  the  second  place  the  chemical  action  is  mostly  confined  to 
the  entrance  of  the  pulp  canal  in  the  pulp  chamber,  but  may 
extend  half  way  the  length  of  the  root.  For  this  reason  it  is 
important  that  the  operator  should /«//  the  bristle  up  and  down 
once  or  twice,  so  that  the  surplus  acid  ma}-  come  in  contact  with 
the  extreme  end ;  but  it  being  difficult  sometimes  to  find  the 
entrance,  the  bristle  should  not  be  pulled  entirely  out  of  the 
canal  after  an  entrance  has  once  been  gained. 

(i8) 


(3)  "  Do  you  advise  filling  the  roots  of  teeth  when  there  is 
inflammation,  etc.  ?  " 

As  a  rule,  a  tooth  containing  a  putrescent  pulp  and  mephitic 
gases,  partially  distended,  and  tender  to  the  touch  with  more  or 
less  pericementitis,  should  never  be  treated  to  any  very  great 
extent  at  the  first  sitting.  Open  into  the  pulp  chamber  and  re- 
move the />«//>  in  tin-  pulp  chamber  only;  apply  counter  irritation 
to  the  gum;  introduce  a  loose  pellet  of  cotton  into  the  cavity 
and  dismiss  the  patient  for  twenty-four  hours.  Any  attempt  to 
extirpate  the  pulp  in  the  root-canals  of  such  teeth  at  the  first 
sitting  is  very  liable  to  cause  more  irritation,  if  not  ulceration. 

Frequently  an  abscess  can  be  aborted  by  the  application  of 
two  or  three  leeches  to  the  gum,  at  a  distance  of  a  half  to 
three-quarters  of  an  inch  from  the  seat  of  trouble — one  leech  is 
of  little  use. 

Fill  at  the  second  sitting,  having  first  extirpated  as  much 
of  the  pulp  as  possible. 

(4)  "Why  not  first  put  the  broach  in  the  acid  and  then  in- 
sert it  into  the  root-canals?  " 

For  the  simple  reason  that  such  a  procedure  would  not 
permit  of  proper  disinfection,  or  destro}-  the  micro-organisms  in 
the  canal.  The  ent^-  of  the  acid  would  be  wasted  upon  the 
metal  and  the  chemical  result  would  be  ////. 

(5)  "Can  a  root-canal  in  a  tooth  with  an  exposed  pulp  be 
filled  by  the  Method  without  destroying  the  life  of  the  pulp  ?  " 

Always  devitalize  the  pulp  in  the  usual  manner  before  util- 
izing the  Method. 

(6)  "  Is  it  necessary  to  extirpate  the  dead  pulp  ?  " 
Alwaj's  remove  the  dead  pulp  in  the  pulp  chamber,  and  as 

much  as  possible  in  the  root-canals  that  will  permit  of  being 
removed  with  a  barbed  broach. 

(7)  "  Can  the  root-canals  be  filled  immediately  ?  " 

Yes  ;  but  this  should  be  left  to  the  discretion  of  the  operator. 

(8)  "  Can  they  be  filled  permanently  ?  " 

Permanency  is  only  a  comparative  term  ;  there  is  no  such 
thing  as  absolute  pennanency  in  anything.  Read  what  the 
chemist  has  said  in  this  connection. 

(g)  "A  tooth  with  an  exposed  pulp  was  devitalized  one 
week  ago.  When  one  of  the  metallic  points  was  inserted  life  was 
apparent  at  the  apex.  In  such  a  ca.se  can  the  broach  be  intro- 
duced, the  liquid  applied  and  the  canal  filled?  " 

In  freshly  devitalized  teeth  there  is  verj-  likely  to  be  more  or 
less  sensation  (if  not  some  pain  to  the  patient)  at  the  apex  of  the 


pulp  canals,  when  a  broach  is  introduced.  The  acid,  plus  the 
chloro-nitrates,  however,  coagulates  live  animal  matter  as  quick- 
ly as  dead  or  semi-dead  matter.  I  fail  to  see  why  permanency  of 
asepsis  should  not  be  probable  in  such  a  case.  See  the  chemis- 
try relating  to  th^  germicidal  effect,  etc. 

(10)  "  How  long  have  you  used  the  Method  ?  " 
For  a  period  of  over  Xjia  years. 

(11)  "  Have  you  ever  fille  1  the  roots  of  teeth  in  the  mouth 
and  afterward  extracted  the  teeth  and  noted  the  condition  ot  the 
root-canals? " 

In  two  different  cases,  two  superior  molars  were  filled,  and 
the  teeth  sacrificed  one  week  later.  The  roots  of  the  teeth 
ware  filed  away  and  the  canals  found  to  be  filled  to  the  apex  of 
each  root.  The  application  of  the  peroxide  of  hydrogen  to  the 
exposed  pulp  canals  showed  the  complete  absence  of  pus.  No 
trouble  followed  the  operation  in  either  case. 

(12)  '■  Should  a  root-canal  be  filled  where  there  is  a  'blind 
abscess  '  ? " 

No  s\-stem  ever  was  devised  for  filling  root-canals  or  ever 
will  be  devised,  in  the  writer's  opinion,  that  will  preclude  the 
possibility  of  root  disturbance,  in  some  cases,  after  filling. 
Where  the  so-called  "blind  abscess"  exists,  or  where  from  an 
internal  putrid  condition  of  the  root-canal,  the  pericementum 
is  in  an  irritable  condition;  a  predisposition  to  inflame  makes 
ulceration  very  probable.  The  condition  of  affairs  is  chronic 
or  sub-acute.  Over-medication,  or  the  careless  introduction  of 
steel  broaches  into  the  canal,  in  fact,  anything  which  adds 
burden  to  the  unhealthy  pericementum  is  very  apt  to  lead  up 
to  an  acute  stage — the  sequel  being  congestion  and  inflamma- 
tion of  the  surrounding  tissues. 

(13)  "  Will  you  please  give  me  your  opinion  of  the  follow- 
ing case,  and  inform  me  why  root  disturbance  followed  the 
operation  ?  " 

"  Mr.  S.  A.  presented  himself  with  a  right  superior  central, 
crown  mostly  decayed  away,  with  dead  and  putrescent  pulp. 
Filed  the  crown  off  nearly  to  the  level  of  the  gum,  with  view 
of  inserting  a  Richmond  crown  ;  removed  dead  pulp  with 
barbed  broach,  and  enlarged  root-canal  with  engine  burs. 
Dressed  with  antiseptic  dressing  and  dismissed  patient.  On 
returning  the  following  day.  the  root  was  found  to  be  very 
tender  to  the  touch,  and  the  gum  considerably  swollen.  The 
swelling  continued  for  three  Aays,  when  the  gum  was  lanced 
and  a  large  quantity  of  pus  discharged.  The  patient  never 
had  any  previous  trouble  with  the  tooth." 

(20) 


The  fact  that  your  patient  had  never  experienced  any  pre- 
vious trouble  with  the  tooth  would  militate  greatly  against  the 
probability  of  an  existing  "  blind  abscess."  It  may  be  assumed 
that  in  this  case  the  apical  foramen  was  open  and  that  a  minute 
quantity  of  septic  inattcv  was  pushed  through  the  end  of  the 
root.  As  I  have  stated  in  answer  to  another  and  somewhat 
similar  question  the  pericementu^i"  of  such  teeth  is  in  an 
inflamed  condition  and  ready  to  go  into  hysterics  on  the  slight- 
est provocation. 

Such  root  canals  are  often  filled  with  a  mephitic  gas, 
which,  if  forced  through  the  foramen,  produces  the  same  in- 
flammatory effect  that  is  produced  by  septic  matter.  It  is  alto- 
gether likely  that  )Ou  did  too  much  to  the  tooth  at  the  flrst 
sitting.  If  you  had  been  content  to  rest  after  you  had  filed  off 
the  crown,  or  after  you  had,  with  a  spoon-shaped  instrument, 
scooped  out  a  little  of  the  putrescent  pulp,  dismissed  your 
patient  for  twenty-four  hours  without  introducing  an  instni- 
ment  into  the  canal,  or  even  dressing  with  cotton  ;  in  other 
words,  if  you  had  first  given  vent  to  the  poisonous  gases  pre- 
sumably contained  in  the  canal,  the  probability  is  that  your 
patient  would  have  been  saved  three  or  four  days  intense 
suffering. 

Again,  if,  in  view  of  the  necessity  of  crowning  at  the  first 
sitting,  you  had  twisted  a  little  cotton  around  the  point  of  one 
of  the  sensitized  bristles,  dipped  the  same  in  the  acid,  and 
quickly  inserted  into  the  canal,  the  dead  animal  matter  con- 
tained in  the  canal  near  the  pulp  chamber  would  have  been 
coagulated,  and  the  mephitic  gases  eliminated  with  the  newly- 
formed  gases  generated  by  the  action  of  the  acid  upon  the  zinc. 
Had  you  then  repeated  the  operation  carrying  the  bristle  nearly 
to  the  apical  foramen,  the  chances  of  root  disturbance  would 
have  been  about  one  in  a  hundred. 

(14)  "  Does  the  Chemico-Metallic  Method  for  filling  root- 
canals  disinfect  the  dead  animal  matter,  or  the  so-called  &^n- 
Xinaljibnllae  in  the  roots?  " 

To  understand  the  rationale  of  the  process  of  disinfection 
by  the  Chemico-Metallic  Method,  bear  in  mind  that  one  of 
the  principal  factors  in  producing  asepsis  is  the  chlorine 
gas  with  which  the  acids  are  charged,  or  which  is  formed  by 
the  chemical  action  of  the  acids  upon  the  metallic  points. 
Both  nitrous  and  chlorine  gases  are  powerful  germicides,  and 
when  generated  in  a  root-canal  must,  at  least,  to  some  extent, 
permeate  the  dentinal  tubuli  and  disinfect  the  dead  dental 
fibres.  • 

(21) 


It  miy  hi  observed  in  tliis  connection,  however,  that  if  the 
pulp  in  a  pulp  canal  be  completely  removed,  before  putrefaction 
sets  in,  the  chances  of  irritation  or  root  disturbance  will  be  very 
remote.  The  palatine  root-canal  of  the  superior  molar,  which 
is  easy  of  access,  favors  the  complete  removal  of  the  pulp,  and 
seldom  gives  trouble.  It  is  upon  the  attenuated,  trirtuous 
roots  of  molars  which  abscesses  usually  form. 

(15)  ' '  Please  inform  me  if  there  is  any  danger  of  discolora- 
tion in  using  the  Method  ?  " 

No.  How  can  there  be,  when  the  points  are  composed 
principally  of  zinc,  and  the  generation  of  chlorine  gas  a 
factor  ?  If  anytliing,  the  Method  tends  to  bleach,  rather  than 
discolor. 

(16)  "Will  you  kindly  inform  me  if,  before  introducing 
into  the  root-canals  your  points,  it  will  answer  the  same  pur- 
pose if  I  smear  them  with  the   '  balsam  of  the  desert '  ?  " 

Imitation  is  the  sincerest  form  of  a  compliment.  '  'Balsam 
of  the  desert"  has  no  chemical  action  on  the  metallic  points; 
it  does  not  prevent  a  putrefactive  condition.  li  is  not  a  germ- 
icide. To  utilize  the  points  without  the  application  of  the 
liquid  chemicals  would  have  its  parallel  in  the  pla}'  of  'Ham- 
let," with  Hamlet  left  out. 

(17)  "  Please  inform  me  how  it  is  that  a  tooth  composed  of 
the  phosphate  and  carbonate  of  lime,  which  I  have  always 
supposed  to  be  sensitive  to  the  action  of  acids,  is  not  attacked 
and  dissolved  before  the  metallic  points  as  claimed  b}^  you?  " 

This  is  a  question  which  a  chemist  should  answer,  and  I 
refer  you  to  the  Chemical  Query,  number  4,  answered  by 
the  chemist.  If  you  will  take  the  trouble,  however,  to  drop 
a  small  piece  of  the  enamel  of  a  tooth  into  the  dental  acid,  and 
then  a  small  piece  of  one  of  the  metallic  points,  you  will  be 
convinced  that  the  former  is  more  resistant  to  the  action  of  the 
acids  than  the  latter. 

The  question  arises  whether  the  nascent  chlorine  gas  which 
is  generated  in  the  pulp  canal,  plus  the  influence  of  the  acid, 
tends  to  a  slight  loss  of  tooth  substance,  and  the  formation  of 
lime  phosphates  around  the  metallic  point. 

It  is  known  that  chlorine  has  but  little  attraction  for 
oxygen,  its  energies  being  principally  exerted  towards  hydro- 
gen and  the  metals.  In  this  connection  it  may  be  again 
observed  that  the  metallic  points  are  composed  principally  of 
zinc,  which  is  one  of  the  most  susceptible  of  metals  to  the 
-action  of  acids.  ^ 

'22) 


(  iS)  "  Please  inform  me  if  there  is  not  some  other  chemi- 
cal that  will  answer  the  same  purpose  and  be  substituted  for  the 
acids  you  employ  ?  " 

If  the  root-canals  were  large  enough  to  admit  the  introduc- 
tion of  a  formaldeh^-de  lamp  perhaps  formaldehyde  would  be 
the  best  substitute  as  a  disinfectant.  The  Chentieo-Mctallic 
Method  means,  not  only  thorough  disinfection,  but  perfect 
filling  at  the  same  time.  It  means  the  generation  of  nitrous- 
chlorine  gas  in  the  root- canals ;  the  coagulation  of  the  dead 
animal  matter,  the  formation  of  the  so-called  albuminates,  and 
finally  permanent  asepsis  through  the  influence  of  a  powerful 
germicide.  . 

{19)  "  Kindly  inform  me  how  j-ou  would  proceed  to  disin- 
fect a  large  putrid  canal,  in  a  root  you  desired  to  crown  at  the 
first  sitting  ?  ' ' 

Insert  one  of  the  sensitized  broaches  into  a  broach-handle  ; 
twist  a  I'cry  little  cotton  around,  nearh-  the  whole  length  of  the 
broach  ;  bend  over  the  point  against  the  cotton,  as  the  barb 
on  a  straight  fish-hook  might  be  pressed  down ;  dip  the 
broach  into  the  acid,  quickly  carry  into  root-canal,  and  pull  up 
and  down.  Repeat  this  operation  once  cr  twice,  and  in  one 
minute's  time  the  worst  kind  of  a  canal  can  be  thoroughly  dis- 
infected. 

(20)  "  Please  inform  me  if  it  is  necessary  to  use  any  alkali 
to  neutralize  the  acid  after  it  has  come  in  contact  with  one  of 
the  points  in  a  root  canal  ?  " 

The  points  neutralize  the  acid.  A  surplus  of  the  acid 
completely  destroys  the  points  ;  but  a  single  drop,  although 
producing  chemical  action,  only  corrodes  them.  While  at  the 
same  time  it  coagulates  the  animal  matter. 


"Many  a  clever  artist  has  failed,  because 
in  the  pride  of  youthful  facility,  he  has  de- 
clined the  method  and  drudgery  of  a  correct 
technique.'^ 


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